Product dryer

ABSTRACT

A product dryer is disclosed as a tray dryer and is provided with damper means that can be set to provide down draft, updraft, and cross draft treatments of the products substantially without interruption when changes in the draft direction are made. In one embodiment of the invention, the damper means are power operated and have controls mounted outside the dryer where they can be quickly and easily operated to shift from one type of product treatment to another. In another embodiment of the invention, the damper means are manually operated but the operating means are located on the same side of the dryer.

United States Patent La Pan [54] PRODUCT DRYER [72] Inventor: Raymond D. La Pan, 6 River Street, Graniteville, Mass. 01829 [22] Filed: March 5, 1971 [21] Appl. No.: 121,322

521 U.S. c1. ..'34/191, 34/196, 34/225,

[151 3,681,856 51 Aug. 8, 1972 Primary Examiner-Carroll B. Dority, Jr. Attorney-Abbott Spear 57 2 ABSTRACT A product dryer-is disclosed as a tray dryer and is provided with'damper means that can be set to provide down draft, updraft, and cross draft treatments of the products substantially Without interruption when changes in the draft direction are made. In one embodiment of the invention, the damper means are power operated and have controls mounted outside the dryer where they can be quickly and easily operated to shift from one type of product treatment to another. In another embodiment of the invention, the damper means are manually operated but the operating means are located on the same side of the dryer.

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ATTORNEY INVENTOR RAYMOND D. LA PAN C/f ATTORNEY 3.681.856 SHEET 80F 8 PATENTEDAUB 8 m2 INVENTOR ATTORNEY PRODUCT DRYER This invention relates to product dryers, particularly of the tray type.

Product dryers are available that provide for down draft, up draft, and cross draft treatments. Such dryers typically include a series of sections in each of which the product is subject to a desired draft treatment. Usually once the desired sequence of treatments has been determined and established for a particular product, there is no occasion for changing it. The patent to Lambert et al, U.S. Pat. No. 3,281,958, discloses dryers, including pilot models, where changes in the draft can be made but only with the dryer shut down. v

Problems exist, however, in determining either the sequence of treatment or the optimum treatment of a product. Tray dryers are well suited for such experimental purposes provided they make possible the exposure of the product to the different possible treatments as well as provide for suitable control of time and temperature. Presently available tray dryers, while making test treatments possible, are unsatisfactory in that considerable time is lost in shifting from one type of treatment to another. While the technicians time is important, it is often more important to be able to more closely simulate a production dryers operation in which there is practically no interval in which the product is not being treated.

The general objective of the present invention is to provide tray dryers in which the time required to shift from one product treatment to another is minimized, an objective attained with a dryer comprising a chamber having upper and lower horizontal conduits, vertical conduits, and first and second passageways between the vertical and horizontal conduits. A blower in one vertical conduit has its inlet in communication with the first passageway and the second passageway has means enabling the product to be supported therein. There are openings effecting communication between the horizontal conduits and both the vertical conduits and the two passageways. There are also openings effecting communication between the first and second passageways and between the second passageway and the other vertical conduit. Damper means are provided for each opening and are operable to enable adjustments to be quickly and easily made to effect up, down, or cross draft treatments of the product in the second passageway.

Another objective of the invention is to facilitate the operation of the damper means, an objective attained by the use of power operated devices to set the damper means in either their open or their closed positions or by the use of manually operated controls located on the outside of the dryer where they may be quickly and easily operated.

Another objective of the invention is to minimize the number of controls that need to be operated to effect a change in draft direction, an objective attained by providing that a first control effects the opening or closing of the damper means between the vertical conduit in which the blower is located and the lower horizontal conduit and the closing or the opening of the damper means between that horizontal conduit and the first passageway. A second control effects the opening or the closing of the damper means between that verti cal conduit and the upper horizontal conduit and the fle means so interconnected that they turn as a unitbetween open and closed positions and with one pivot either extending through a wall of the dryer and provided with a manual or power op'eratedcontrol or connected to a damper means that is so provided.- Where the-baffle means are, manually operated, the manual controls are alllocated on the same side of the dryer.

Yet another'objective of the present invention is to provide effectivecontrol of the temperature of the circulating air, an objective attained by providing the first passageway with a baffle structure defining a chamber between the blower inlet and any fresh air inlet, or any return opening. Heating means are located in that chamber as are the wet and dry bulbs of a temperature controller also having a dry bulb thermometer on the opposite or inlet side of the heating means.

A further objective of the invention, when the heating means require an exhaust, is to utilize that exhaust in heat exchanging relation with the inlet air, an objective attained by using an exhaust pipe in communication with an exhaust stack and extending through the major portion of the air inlet.

Another objective of the invention is to provide for means enabling the effective cross sectional area of the second vertical passageway to be varied to enable the drier to be used with trays of various sizes.

In the accompanying drawings, there are shown embodiments of the invention from which these and other of its objectives, novel features, and advantages will be readily apparent.

IN THE DRAWINGS:

FIG. 1 is a view of the front of a dryer in accordance with the invention;

FIG. 2 is a rear view thereof;

FIG. 3 is a view of the fan end of the dryer;

FIG. 4 is a vertical section through the vertical passageway in which the product is supported;

FIG. 5 is a fragmentary top plan view of the dryer;

FIG. 6 is a fragmentary view, on an increase in scale, showing a typical baffle means;

FIG. 7 is a schematic view illustrating up draft flow through the second passageway;

FIG. 8 is a like view illustrating cross draft circulation;

FIG. 9 is a like view illustrating down flow circulation; and

FIG. 10 is a front view of a dryer in accordance with another embodiment of the invention.

The dryer illustrated by FIGS. 1 9 comprises a chamber, generally indicated at 20 having a door 2] in the end wall 22 and a like door 23 in the end wall 24.

The internal framework of the chamber 20 includes transversely aligned upper and lower members 25 and .a vertical conduit generally indicated at 37.

' ports the intake 33"of a blower 34 which is within the conduit 32 and mounted on the door 21 The blower 34 is separable from its intake 33. The walls 29 and 30.

define a first passageway generally indicated at 35 into which'the blower intake 33 opens; The walls 30 and 31 together "establish a second passageway, generally indicated at 36. The wall 31 and the end wall 24 establish The two vertical conduits 32 and 37 and the two passageways 35 and 36 open into the space above the members 25 which space constitutes an upper horizon tal conduit generally indicated at 38 and also into the space below the members 26 with that space constituting a lower horizontal conduit generally indicated at It will be noted that the wall 29 has horizontal extensions .40 each forming a boundary between the passageway 35 and the proximate horizontal conduit with the openings between that passageway and the horizontal conduits being of approximately the same size as those of the vertical conduits 32 and 37. The wall extensions 40 have portions 41 extending towards each other and then towards the wall 29 to provide a baffled chamber 42 for the blower inlet 33. The openings between both the vertical conduits and the two passageways and the horizontal conduits are provided with damper units by which they may be closed. The upper and lower damper units of the conduit 32 are indicated generally at 43 and 44, respectively, and those of the conduit 37 at 45 and 46, respectively. The upper and lower damper units of the passageway 35 are indicated generally at 47 and 48 and the corresponding damper units of the passageway 36 are indicated generally at 49 and 50. Desirably, air splitters 51 are located above andbelow the damper units 43 and 44.

It will be noted from FIG. 1 that the front wall 27 of the chamber 20 has a door 52 above which there is an inspection window 53. The door 52, when opened, enables a tray 54 to be inserted in or removed from the second passageway 36. A pair of channels 55 secured to supports 56 establish a slideway for the margins of the tray 54. It will also be noted that each of the walls 30 and 31 has a vertically spaced pair of damper con trolled ports separated by the appropriate one of the channels 55. The ports of the wall 30 are identified by their generally indicated damper units 57 while those of thewall 31 are identified by their generally indicated damper units 58.

Each damper unit, of which the unit 45 is an example, consists, see FIG. 6, of a series of dampers 59 with each having central pivots 60 supported by appropriate ones of the frame members transversely of the dryer. The dampers of each unit have arms 61 to each of which a connecting rod 62 is pivotally connected. One end of one damper pivot 60 of each damper unit extends through a side wall of the chamber 20 so that by turning that pivot in one direction or the other as by means subsequently described that damper unit can be opened or closed.

It will be noted that the-chamber has a damper controlled fresh air inlet 63, see FIGS. 2, 3, and. 5, opening through its rear wall 28 into 'the first passageway 35 which is also provided with heating means. While the heating means may be of any type, gas heaters are relatively frequently desired and such may comprise a pair of U-shaped burner tubes 64 provided with fins 65 and having their inlet ends secured to the rear wall 28 by mounts 66 and their other ends provided with exhaust pipes 67 extending as pre-heaters through the air inlet 63 and into the exhaust stack 68 whose upper end is in communication with the exhaust fan 69. The burner tubes 64 are shown as located in the blower inlet chamber 42.

The exhaust stack 68 has a port 70 in communication with the upper horizontal conduit 38 and controlled by a damper 71. The stack 68.also has a port 72 incom munication with the lower horizontal conduit 39 and the conduits through the passageway 36 and back to the passageway 32 to treat the product with an up draft, down draft, or cross draft circulation.

Up draft treatment, see FIG. 7, is effected with the damper unit 43 closed, the damper unit 44 open, the damper unit 47 open and the damper unit 48 closed. Both damper units 49 and 50 are open and the damper units 45, 46, 57, and 58 closed. Air, accordingly, is directed by the blower downwardly into the lower horizontal conduit 39, upwardly through the second passageway 36 and the product therein and into the upper horizontal conduit 38 and then returned downwardly into the first passageway 35. I

Down draft circulation of the air, see FIG. 9, is effected simply by opening the damper unit 43, closing the damper unit 44, opening the damper unit 48 closing the damper unit 47. With these changes, the circulation is reversed through the product.

Where cross draft treatments are wanted, see FIG. 8, both the damper-units 43 and are open and the damper units 47, 48,' 49, and 50 are closed. The damper units 45 and 46 in the vertical conduit 37 are opened as are the damper units 57 and 58 thereby enabling air to flow into the conduit 37 through both horizontal conduits, transversely through the passageway 36 and the product therein and back into the passageway 35.

It is preferred that the change in settings of the damper units be effected by power operated means shown as air-operated pistons and reference is made to FIGS. 2, 7, 8, and 9.

In the case of the damper units 43 and 47, it will be noted that when either one is open, the other is closed. The units 43 and 47 are shown as controlled by pistoncylinder units 75 and76, respectively, in an air circuit 77 controlled by a valve 78 operable to deliver air to either side of the pistons of the units 75 and 76 and simultaneously vent air from the opposite side thereof. The circuit provides for the simultaneous opposite movement of the piston of the units 75 and 76. The unit 75 is connected to an arm 79 fast on the end of the pivot 60 of the damper unit 43 that extends through the rear wall 28 of the housing and the unit 76 is connected to the arm 80 fast on the corresponding pivot 60 of the damper unit 47.

Similarly, whenever the damper unit 44 is open, the damper unit 48 is closed and vice versa. For that reason the units '44 and 48 are opened and closed in the same manner as the damper'units 43 and 47. The air circuit 81 includes a valve 82 identical to the valve 78 and is connected to piston-cylinder units 83 and 84 in the same manner as in the case of the air circuit 77. The piston-cylinder unit 83 is connected to an arm 85 fast on the end of the pivot 60 of the damper unit 44 that is exposed at the rear of the housing and the pistoncylinder unit 84 is connected to the arm 86 on the corresponding pivot 60 of the damper unit 48.

The damper units 45 and'46 of the conduit 37 are either both open or closed. For that reason their pivots 60 that extend through the rear housing wall 28 are provided with arms 87 and 88, respectively, interconnected by a link 89 so that a single air-operated pistoncylinder unit 90 may control both of them. The unit 90 is an air circuit 91 under the control of a valve 92 similar to the valves 78 and 82. The unit 90 is connected to one end of the link 89. As the damper units 49 and 50 are both either open or closed, being closed only during cross draft treatments, they may both be operated by the piston-cylinder unit 93 in the circuit 91 but arranged to open the damper units 49 and 50 only when the damper units 45 and 46 are closed. To that end, the pivots 60 ofthe damper units 49 and 50 that the air prior to being heated. The recorder 101 also has dry and wet bulb temperature sensors 103 and- 104 located between the heaters 64 and the blower intake While the slideway established by the channels 55 in the passageway 36 is for a tray 54 of the same cross sectional area as that of the passageway, it may be desirableto use a tray of a smaller size such as the tray 105. In order that such a smaller tray can be used, the door 23 is opened and a- U-shaped baffle 106 is inserted therethrough and positioned to block flow through the passageway 36 rearwardly of the tray 105.

Reference is now made to' the embodiment of the invention illustrated by FIG. 10. The dryer in accordance with this embodiment is generally similar to that described except for the control of damper settings'and accordingly like reference numerals, distinguished by the suffix addition A, are employed to designate corextend through the rear housing wall 28 are provided with arms 94 and 95, respectively interconnected by a link 96 connected to the piston-cylinder unit 93. Similarly, since the damper units 57 and 58 are both open only during cross draft treatments, their pivots 60 that extend through the rear housing wall 28 have arms 97 and 98 interconnected by a link 99 and operated by a single piston-cylinder unit 100 in the air circuit 91 so that the damper units 57 and 58 are open only when the damper units 49 and 50 are open.

With this arrangement, it is only necessary to adjust the three valves 78, 82, and 92 between first and second positions and these may be mounted close together on a front panel on the front wall 27 thereby to enable changes in air circulation to be quickly and easily effected without any appreciable interruption of product treatment. The valve positions may, of course, be marked. With one of the two'positions of the valve 78 marked UP DRAFT and the other DOWN or CROSS DRAFT. The valve 82 may have one of its positions marked DOWN DRAFT and the other position UP or CROSS DRAFT. One position of the valve 92 may be marked UP or DOWN DRAFT and the other as CROSS DRAFT. It-will be noted that it is never necessary to set more than two valves.

In practice, it is usually necessary to be able to determine the temperature and humidity conditions within the housing. To that end, an instrument 101, the Dual Temperature and Humidity Controller, Model RC66, manufactured by The Foxboro Company, for example, is used. The instrument 101 has a dry bulb temperature sensor 102 located in the first passageway 35 in a position to be responsive to the temperature of responding parts. Each'damper unit in the embodiment of the invention has a knob mounted on the end of its shaft 60A that'extends through the front wall 27A of the chamber 20A. The damper unit.43A has a knob 107, the unit 44A,;a knob 108, the damper units 47A and 48A, knobs 109 and 110, respectively, and the damper units 45A and 46A, knobs 111 and 11 2, respectively. The damper unit 49A and 50A have knobs 113 and 114, respectively, and the damper units 57A and 58A are provided with knobs 115, and 116, respectively. As all the knobs are on the same side of the chamber 20A and may be marked in the manner previously indicated, changes in the flow of fluid through the product in the passageway 36A may be effected with the blower in operation without material interruption of the treatment even though not as quickly and easily as in the first described embodiment but permitting of different combinations of damper settings and a variation in the extent to which they are opened.

The dryer 20A is otherwise quite similar to the dryer- 20 except that it has a damper controlled inlet port 1 17 opening into the passageway 35A through the front wall 27A.

I claim:

'1. Apparatus for use in effecting product treatment with a fluid stream, said apparatus comprising a chamber including upper and lower horizontal conduits, vertical conduits, and first and second passageways between said horizontal and vertical conduits, a blower in one vertical conduit with its intake in communication with the first passageway, product supporting means in the second passageway, openings between the horizontal conduits and both said vertical conduits and said passageways, openings effecting communication between the first and second passageways and between the second passageway and the other vertical conduit, and damper means in control of each opening and selectively operable to provide fluid circulation through appropriate ones of the conduits from the first passageway through the second passageway and back to the first passageway with the fluid flow through the second passageway being upwardly, downwardly, or transversely thereof.

2. The apparatus of claim 1 in which the damper means include control members, one for each damper means and all control members are located on the same side of the chamber.

3. The apparatus of claim 1 in which each of the damper means comprises a plurality of dampers, each .damper including a pivot at each end supported within the chamber transversely thereof, one pivot end of one damper of each of the damper means extending through the same side of the chamber and a control member fixed on the exposed extremity thereof, each damper also including an arm, and a connecting rod to which each arm is pivotally connected.

4. The apparatus of claim 1 in which the damper means in control of the openings between the second operable either to maintain the first unit open and the secondandthird units closed or the second and third units open and the first unit closed.

6. The apparatus of claim 1 and power operated means in control of the damper means and including adjustable controls mounted on a side of the chamber.

7. The apparatus of claim 6 in which the power operated means are of a fluid pressure operated type and the controls are valves.

8. The apparatus of claim 6 in which there arethree adjustable controls, the first operable to open or close the damper means between the blower conduit and the lower horizontal conduit and close or open the damper means between the first passageway and said lower conduit, the second operable to open or close the damper means between the blower conduit and the upper horizontal conduit and to close or open the damper means between the first passageway and said upper conduit, and the third operable to open or close both of the damper means between the second passageway and said horizontal conduits and close or open both damper means between the other vertical' conduit and said horizontal conduits and close or open both damper means that permit cross draft circulation through the second passageway.

9. The apparatus of claim 8 in which the two damper means between the second passageway and the horizontal conduits are interconnected to be adjusted as a unit, the two damper means between said other vertical conduits and the horizontal conduits are interconnected to be adjusted as a unit, and the two damper means operable to permit cross draft circulation through the second passageway and also interconnected to be adjusted as a unit. i I

10. The apparatus of claim 9 in which the power operated means are air-operated piston-cylinder units, one for each of the damper means operated by the first two adjustable controls and one for each of the interconnected dampermeans operated by the third adjustable control and the adjustable controlsare valves having two positions enabling the piston-cylinder units,

to be reciprocated.

11. The apparatus of claim 1 in which the first passageway has a fresh air inlet.

12. The apparatus of claim 1 in which the first passageway includes heating means.

13. The apparatus of claim 1 and baffle means between the damper means between the first passageway and the two horizontal conduits and the in take of the blower and defining an intake chamber and heating means within the intake chamber. 7

14. The apparatus of claim l3and temperature and humidity control means including a dry bulb thermometer adjacent the outer end of the intake chamber and wet and dry bulb controls between the heating means and the intake of the blower.

15. The apparatus of claim 11 and heating means including an exhaust with which the fresh air inlet is in heat exchanging relationship.

16. The apparatus of claim 1 and an air exhaust including damper controlled inlets, one in comm unica tion with each horizontal conduit.

17. The apparatus of claim 16 and heating means in the first passageway including an exhaust pipe opening into the air exhaust.

18. The apparatus of claim 17 and an air inlet through which the exhaust pipe extends.

19. The apparatus of claim 1 in which the product I supporting means includes a slideway for a tray of a length and widthv approximately equal to the length and width of the second'passageway, and means insertable in the second passageway and operable to block a rear portion thereof against circulation therethrough thereby to enable a pan of the same width but lesser length to be used. 

1. Apparatus for use in effecting product treatment with a fluid stream, said apparatus comprising a chamber including upper and lower horizontal conduits, vertical conduits, and first and second passageways between said horizontal and vertical conduits, a blower in one vertical conduit with its intake in communicaTion with the first passageway, product supporting means in the second passageway, openings between the horizontal conduits and both said vertical conduits and said passageways, openings effecting communication between the first and second passageways and between the second passageway and the other vertical conduit, and damper means in control of each opening and selectively operable to provide fluid circulation through appropriate ones of the conduits from the first passageway through the second passageway and back to the first passageway with the fluid flow through the second passageway being upwardly, downwardly, or transversely thereof.
 2. The apparatus of claim 1 in which the damper means include control members, one for each damper means and all control members are located on the same side of the chamber.
 3. The apparatus of claim 1 in which each of the damper means comprises a plurality of dampers, each damper including a pivot at each end supported within the chamber transversely thereof, one pivot end of one damper of each of the damper means extending through the same side of the chamber and a control member fixed on the exposed extremity thereof, each damper also including an arm, and a connecting rod to which each arm is pivotally connected.
 4. The apparatus of claim 1 in which the damper means in control of the openings between the second passageway and the horizontal conduits are interconnected to be operated as a first unit, the damper means in control of the openings between the second passageway and the first passageway and said other vertical conduit are interconnected to be operated as a second unit, and the damper means in control of the openings between said other vertical conduits and the horizontal conduits are interconnected to be operated as a third unit.
 5. The apparatus of claim 4 and means to control all of said units and located outside the chamber and operable either to maintain the first unit open and the second and third units closed or the second and third units open and the first unit closed.
 6. The apparatus of claim 1 and power operated means in control of the damper means and including adjustable controls mounted on a side of the chamber.
 7. The apparatus of claim 6 in which the power operated means are of a fluid pressure operated type and the controls are valves.
 8. The apparatus of claim 6 in which there are three adjustable controls, the first operable to open or close the damper means between the blower conduit and the lower horizontal conduit and close or open the damper means between the first passageway and said lower conduit, the second operable to open or close the damper means between the blower conduit and the upper horizontal conduit and to close or open the damper means between the first passageway and said upper conduit, and the third operable to open or close both of the damper means between the second passageway and said horizontal conduits and close or open both damper means between the other vertical conduit and said horizontal conduits and close or open both damper means that permit cross draft circulation through the second passageway.
 9. The apparatus of claim 8 in which the two damper means between the second passageway and the horizontal conduits are interconnected to be adjusted as a unit, the two damper means between said other vertical conduits and the horizontal conduits are interconnected to be adjusted as a unit, and the two damper means operable to permit cross draft circulation through the second passageway and also interconnected to be adjusted as a unit.
 10. The apparatus of claim 9 in which the power operated means are air-operated piston-cylinder units, one for each of the damper means operated by the first two adjustable controls and one for each of the interconnected damper means operated by the third adjustable control and the adjustable controls are valves having two positions enabling the piston-cylinder units to be reciprocated.
 11. The apparatus of claim 1 in which tHe first passageway has a fresh air inlet.
 12. The apparatus of claim 1 in which the first passageway includes heating means.
 13. The apparatus of claim 1 and baffle means between the damper means between the first passageway and the two horizontal conduits and the intake of the blower and defining an intake chamber and heating means within the intake chamber.
 14. The apparatus of claim 13 and temperature and humidity control means including a dry bulb thermometer adjacent the outer end of the intake chamber and wet and dry bulb controls between the heating means and the intake of the blower.
 15. The apparatus of claim 11 and heating means including an exhaust with which the fresh air inlet is in heat exchanging relationship.
 16. The apparatus of claim 1 and an air exhaust including damper controlled inlets, one in communication with each horizontal conduit.
 17. The apparatus of claim 16 and heating means in the first passageway including an exhaust pipe opening into the air exhaust.
 18. The apparatus of claim 17 and an air inlet through which the exhaust pipe extends.
 19. The apparatus of claim 1 in which the product supporting means includes a slideway for a tray of a length and width approximately equal to the length and width of the second passageway, and means insertable in the second passageway and operable to block a rear portion thereof against circulation therethrough thereby to enable a pan of the same width but lesser length to be used. 